1. Field of the Invention
This invention generally relates to an imaging apparatus such as a video camera, and particularly relates to an imaging apparatus including solid-state image sensors and a section for processing video signals outputted from the image sensors to attain a high video definition. In addition, this invention relates to a method of processing video signals to attain a high video definition.
2. Description of the Related Art
Japanese patent application publication number 2000-341708 discloses an imaging apparatus including a lens, a prism, and solid-state image sensors for R, G, and B (red, green, and blue). An incident light beam passes through the lens before reaching the prism. The incident light beam is separated by the prism into R, G, and B light beams applied to the R, G, and B image sensors respectively. The R, G, and B light beams are converted by the R, G, and B image sensors into R, G, and B signals, respectively. Each of the R, G, and B image sensors has a matrix array of 640 photosensor pixels in a horizontal direction and 480 photosensor pixels in a vertical direction. The matrix array of the photosensor pixels has a predetermined horizontal pixel pitch and a predetermined vertical pixel pitch.
In the imaging apparatus of Japanese application 2000-341708, the optical position of the R and B image sensors relative to the incident light beam slightly differs from that of the G image sensor such that the photosensor pixels in the R, G, and B image sensors are staggered at horizontal intervals equal to half the horizontal pixel pitch and vertical intervals equal to half the vertical pixel pitch. The R, G, and B signals outputted from the R, G, and B image sensors are processed, through interpolation, into component video signals representing a periodically-updated frame composed of 1280 pixels in a horizontal direction and 720 pixels in a vertical direction.
Japanese patent application publication number 2000-341710 discloses an imaging apparatus including a lens, a prism, and solid-state image sensors for R, G1, G2, and B (red, first green, second green, and blue). An incident light beam passes through the lens before reaching the prism. The incident light beam is separated by the prism into R, G1, G2, and B light beams applied to the R, G1, G2, and B image sensors respectively. The R, G1, G2, and B light beams are converted by the R, G1, G2, and B image sensors into R, G1, G2, and B signals, respectively. Each of the R, G1, G2, and B image sensors has a matrix array of 640 photosensor pixels in a horizontal direction and 480 photosensor pixels in a vertical direction. The matrix array of the photosensor pixels has a predetermined horizontal pixel pitch and a predetermined vertical pixel pitch.
In the imaging apparatus of Japanese application 2000-341710, the optical position of the G2 image sensor relative to the incident light beam slightly differs from that of the G1 image sensor such that the photosensor pixels in the G1 and G2 image sensors are staggered at horizontal intervals equal to half the horizontal pixel pitch and vertical intervals equal to half the vertical pixel pitch. The optical position of the R image sensor relative to the incident light beam slightly differs from that of the G1 image sensor such that the photosensor pixels in the R and G1 image sensors are staggered at horizontal intervals equal to half the horizontal pixel pitch. The optical position of the B image sensor relative to the incident light beam slightly differs from that of the G1 image sensor such that the photosensor pixels in the B and G1 image sensors are staggered at vertical intervals equal to half the vertical pixel pitch. The R, G1, G2, and B signals outputted from the R, G1, G2, and B image sensors are processed, through interpolation, into component video signals representing a periodically-updated frame composed of 1280 pixels in a horizontal direction and 960 pixels in a vertical direction.
Japanese patent application publication number 11-234690/1999 discloses an imaging apparatus including two image sensors each having a matrix array of photosensor pixels. The positions of the two image sensors slightly differ such that the pixel array in one of the two image sensors is obliquely shifted from that in the other image sensor by a distance corresponding to half a pixel in a horizontal direction and a distance corresponding to a half a pixel in a vertical direction. For every frame, a set of output signals from the two image sensors is composed of only first signal segments representing first alternate ones of pixels forming one high-definition frame. Second signal segments representing second alternate ones of pixels forming one high-definition frame are generated from the first signal segments through interpolation depending on the direction of a high video correlation. Specifically, the degree and direction of each of video correlations at and around a pixel of interest are detected. In the presence of a high video correlation along a horizontal direction, a second signal segment representing a pixel of interest is generated from first signal segments representing left and right pixels neighboring the pixel of interest. In the presence of a high video correlation along a vertical direction, a second signal segment representing a pixel of interest is generated from first signal segments representing upper and lower pixels neighboring the pixel of interest. In the absence of such high horizontal and vertical video correlations, a second signal segment representing a pixel of interest is generated from first signal segments representing left, right, upper, and lower pixels neighboring the pixel of interest.
Japanese patent application publication number 10-155158/1998 discloses an imaging apparatus similar to that in Japanese application 11-234690/1999 except for the following points. In the apparatus of Japanese application 10-155158/1998, not only horizontal and vertical video correlations but also oblique video correlations can be detected. In the presence of a high video correlation in a left-upper to right-lower direction, a signal segment representing a pixel of interest is generated from signal segments representing left-upper and right-lower pixels neighboring the pixel of interest. In the presence of a high video correlation along a left-lower to right-upper direction, a signal segment representing a pixel of interest is generated from signal segments representing left-lower and right-upper pixels neighboring the pixel of interest.